Case Presentation: A 61 year old female presented to the emergency department with 1 day of nausea, vomiting, and fever. The day prior to her symptom onset, she had undergone a colonoscopy for colon cancer screening that was normal. Her medical history was notable for splenectomy in 2000 for a hamartoma.On presentation, her temperature was 100.7 F and blood pressure 97/60 mm Hg. Her labwork was notable for hemoglobin 8 g/dL, white blood cell count 12,000/uL, platelets 19,000/uL, lactate 10 mmol/L, INR 3.4, PTT 74 sec, d-dimer >20 ug/mL, fibrinogen 255 mg/dL, and fibrin split products >80 ug/mL, which was concerning for disseminated intravascular coagulation (DIC). CT scan of the abdomen showed pneumatosis intestinalis. She was started on vancomycin, cefepime, metronidazole and underwent exploratory laparotomy which was unrevealing and showed no colonic perforation. She soon progressed into septic and hypovolemic shock requiring vasopressor support. Her DIC continued to worsen, leading to a drop in her hemoglobin to 4 g/dL and a new retroperitoneal hematoma which eventually self-tamponaded. Throughout her hospitalization, she required transfusion with 4 units pRBCs, 4 units FFP, and 3 units of platelets in total. Blood cultures grew Capnocytophaga canimorsus in 4 out of 4 bottles after 17 hours of incubation and her antibiotics were changed to intravenous ampicillin-sulbactam. Once her mental status improved, she reported that she owned 2 dogs, but denied any recent bites or scratches. A thorough skin exam was notable for purpura but no skin breaks. Her symptoms and coagulopathy improved and she was discharged with oral amoxicillin-clavulanic acid for a total antibiotic course of 3 weeks.
Discussion: Capnocytophaga canimorsus is part of the normal oral flora in dogs. The incidence of C. canimorsus bacteremia in humans is low – a national survey in the Netherlands estimated 0.67 cases per million per year. Of these infected patients, about half (43-56%) reported a dog bite. Other routes of transmission have been reported through scratches from dogs and occasionally contact with cat saliva. In the United States, there are approximately 15 million colonoscopies done annually. Transient bacteremia is estimated to occur in about 4% of patients undergoing colonoscopy, but oftentimes is asymptomatic. Despite being an otherwise healthy individual, this patient’s asplenia put her at risk for infection from encapsulated organisms, a known risk factor for C. canimorsus infections. In this case, her bacteremia after her colonoscopy progressed to septic shock and DIC.Here we describe a case of C. canimorsus bacteremia after a colonoscopy without a history of bite or scratch. Given the timing of symptoms after the colonoscopy, it is believed that the patient had been colonized with C. canimorsus prior to the procedure and the colonoscopy led to bacteremia through microtrauma in the colon. While there have been several published case reports on C. canimorsus bacteremia, none have described a case that occurred due to a colonoscopy.
Conclusions: C. canimorsus bacteremia usually occurs after a dog bite or scratch, but other modes of infection, such as a colonoscopy, can occur in patients who may be colonized with the bacteria.For patients who are at risk for severe infection from encapsulated organisms, screening for history regarding animal exposure may help clinicians identify a subset of patients who are at higher risk for post-colonoscopy complications.